Selective Hydrogenation of Butadiene over Non-noble Bimetallic Catalysts
Catalyseurs bimétalliques à base de métaux non nobles pour l'hydrogénation sélective du Butadiène
Résumé
This work investigates the preparation and characterization of titania-supported non-noble bimetallic Cu-Zn, Ni-Zn and Fe-Zn catalysts with various atomic ratios and their catalytic properties for the selective hydrogenation of polyunsaturated hydrocarbons. Co-deposition-precipitation with urea (DPu) and co-deposition-precipitation at fixed pH (DP8) methods were employed for the samples preparation. The metal ions were sequentially deposited onto the TiO2 surface (the sequence of pH for ions deposition being CuII < ZnII ≈FeII < NiII) during the DPu, while they were simultaneously deposited using DP8 method. After sample reduction at proper temperature (350 °C for Cu-Zn, 450 °C for Ni-Zn and 500 °C for Fe-Zn), XRD and STEM-HAADF coupled with EDS showed that bimetallic nanoparticles were formed in Cu-Zn/TiO2 (Cu3Zn1 or Cu0.9Zn0.1 alloy) and Ni-Zn systems (Ni1Zn1 or Ni4Zn1 alloy) with average particle size smaller than 5 nm. Only metallic Fe was detected by XRD in Fe-Zn/TiO2. Zn is inactive for butadiene selective hydrogenation, and acts as a modifier of the monometallic catalysts whose activity follows the sequence: Cu < Fe < Ni. The addition of Zn slightly decreases the activity and influences the selectivity to butenes, but provides much more stable catalysts. The higher stability of the bimetallic catalysts was ascribed to the formation of lower amount of carbonaceous species during the reaction, resulting from the change in the size of the active metal surface ensembles by alloying with Zn.
Ce travail porte sur la préparation et la caractérisation de catalyseurs bimétalliques Cu-Zn, Ni-Zn et Fe-Zn supportés sur TiO2 avec des rapports atomiques variables et sur l'étude de leurs propriétés catalytiques pour l'hydrogénation sélective d'hydrocarbures polyinsaturés. Les méthodes de co-dépôt-précipitation à l'urée (DPu) et co-dépôt-précipitation à pH fixe (DP8) ont été utilisées pour la préparation des matériaux. Les ions métalliques se déposent séquentiellement sur la surface de TiO2 (selon la séquence CuII < ZnII ?FeII
Origine | Version validée par le jury (STAR) |
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https://theses.hal.science/tel-01825025
Soumis le : jeudi 28 juin 2018-01:02:09
Dernière modification le : vendredi 24 mai 2024-05:18:39
Archivage à long terme le : jeudi 27 septembre 2018-01:40:25
Dates et versions
Identifiants
- HAL Id : tel-01825025 , version 1
Citer
Zhao Wang. Selective Hydrogenation of Butadiene over Non-noble Bimetallic Catalysts. Material chemistry. Université Pierre et Marie Curie - Paris VI, 2017. English. ⟨NNT : 2017PA066102⟩. ⟨tel-01825025⟩
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